<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<button>输出</button>
		<script>
			var btn = document.querySelector('button')

			

			btn.addEventListener('click',function(){
				console.log("aaaaaaaaaaaaaaa")
				btn.removeEventListener('click',function(){
					console.log("事件被移除")
				})
			})
		</script>
	</body>
</html>
